Safety Recommendation A-12-069

-From Bryan Bedford, Administrator: Furthermore, as discussed in the meeting, we explained that Unit Load Devices (ULDs) are not part of an aircraft; therefore, tracking implementation of ULDs approved under TSO-C90E, Unit Load Devices, is not feasible. The FAA will survey both cargo operators and manufacturers to determine if there has been a reduction/elimination on the use of ULDs containing plastic and plastic collapsible shipping crates, and implementation of cargo safety improvements in general. Currently, we are formulating an action plan on how best to conduct the surveys and will provide the FAA’s handling details of this safety recommendation in our next response.

I anticipate providing an update to these safety recommendations by September 30, 2026.

We continue to believe the flammability minimum performance requirements for ULDs specified in Technical Standard Order (TSO) C90e are responsive to this recommendation. We note, however, that neither new ULD applications nor those submitted prior to December 2024 are required to comply with TSO C90e. Although you indicated that aircraft manufacturers have a mechanism in place to ensure that this happens, we would like to learn how that process works and if it applies to all ULDs, regardless of when their application was submitted. In addition, we would like to know, for each operator with ULDs, the percentage of ULDs that are compliant with TSO C90e.

Pending our review of the requested information and completion of the recommended actions, Safety Recommendation A-12-69 remains classified OPEN-- ACCEPTABLE RESPONSE.

We acknowledge that our Safety Recommendations Division and your Recommendations Branch are working on scheduling a meeting among the appropriate subject matter experts to discuss these recommendations in more detail, and we look forward to a productive discussion.

Please update us at ExecutiveSecretariat@ntsb.gov on your progress toward addressing these recommendations, and do not submit both an electronic and a hard copy of the same response.

-From Kathryn B. Thomson, Deputy Administrator: The Federal Aviation Administration (FAA) continues to collaborate with industry members such as the Commercial Aviation Safety Team (CAST), consensus standards organizations such as SAE International, safety forums such as the International Civil Aviation Organization, and other regulatory authorities on best practices, technical solutions at the container- and aircraft-levels, and packaging standards that support the safe carriage of goods. As previously reported, SAE International continues to develop battery packaging standards and cargo container and cover solutions that can contain more severe fire loads, including lithium batteries.

As a result of this collaboration, the FAA issued Special Airworthiness Information Bulletin (SAIB) 2023-06, Risk of Uncontrolled Fire Incidents Caused by Aircraft Cargo, on April 4, 2023. This SAIB advises transport category airplane owners and operators of the potential for uncontrolled in-flight fires during carriage of combustible hazardous material.

The SAIB also recommends that aircraft owners and operators take action to mitigate risk, including the use of Class C cargo compartments, fire containment covers, and fire-resistant containers approved to the latest version of Technical Standard Order (TSO) C90e, Unit Load Devices, published on July 6, 2021, which established requirements for classifying a unit load device (ULD) as a fire-resistant container.

The FAA also previously published Advisory Circular (AC) 120-121, Safety Risk Management Involving Items in Aircraft Cargo Compartments, on September 1, 2021, which provides guidance in performing a safety risk assessment, as part of Safety Risk Management, associated with the transport of various types of items in the aircraft cargo compartment and the value of considering the inherent hazardous properties of these items. The SAIB and AC are located at drs.faa.gov.

In addition, the FAA continues to support research and standards by:

• Enabling the development and certification of technologies and systems that enhance the detection of smoke and fumes;

• Promoting the use of halon replacement agents; and

• Ensuring the safety of future fire extinguishing agents for use in cargo compartment fire suppression systems to mitigate the risk of cargo fires resulting from the carriage of hazardous materials, including lithium batteries.

We note that, on July 6, 2021, you published Technical Standards Order (TSO) C90e, Unit Load Devices, which incorporates new standards that address the flammability of cargo container construction materials. We also note that the revised TSO includes new requirements for fire-resistant containers that are based on SAE Aerospace Standard 8992 to screen out highly flammable materials, such as polypropylene.

We believe the flammability minimum performance requirements for ULDs specified in TSO C90e are responsive to this recommendation. We note, however, that they will only affect new ULD applications that are submitted after December 2024, and that ULD designs approved under a previous TSO authorization may still be manufactured after December 2024 under the provisions of its original approval. We would like to know how the FAA plans to ensure that any ULDs manufactured under previous TSO authorizations are brought into compliance with the improved flammability standards specified in TSO C90e.

Pending our review of a plan to address this concern, Safety Recommendation A-12-69 remains classified OPEN-- ACCEPTABLE RESPONSE.

-From Billy Nolen, Acting Administrator, Federal Aviation Administration: The FAA previously informed the Board in its September 30, 2020, letter that once SAE published AS8992, “Fire Resistant Container Design, Performance, and Testing Requirement,” the FAA would revise Technical Standard Order (TSO) C90d, ULD, to include a scalable and tiered fire performance standard, which will require a manufacturer to demonstrate containment of a Class A fire.

AS8992 was published on October 27, 2020, and TSO-C90e was published on July 6, 2021, which includes improved flammability requirements for all new ULD approvals by requiring these designs to meet the Class E cargo liner requirements of § 25.855, Cargo or Baggage Compartments. AS8992 is located at: https://www.sae.org/standards/content/as8992/ and TSO-C90e is located at: drs.faa.gov. I believe that the FAA has effectively addressed Safety Recommendation A-12-69 and consider our actions complete.

We note that you are revising Technical Standards Order (TSO) C90, “Cargo Pallets, Nets and Containers (Unit Load Devices),” to incorporate new standards that address the flammability of cargo container construction materials. We also note that the revised TSO will include new fire resistant container requirements, which are based on SAE Aerospace Standard (AS) 8992, to screen out highly flammable materials, such as polypropylene.

In addition, we note that all Part 121 operators and any Part 135 operators who participate in your voluntary safety management system program are required to have a safety risk management process that includes risk analyses and hazard identification for cargo operations.

We believe your plan is responsive to this recommendation. We are aware that SAE AS 8992, which contains the standards needed to update TSO C90, was published on October 27, 2020. Pending the completion of your planned revisions to TSO C90, Safety Recommendation A-12-69 remains classified OPEN-- ACCEPTABLE RESPONSE.

-From Steve Dickson, Administrator: On May 8, 2020, staff from the Federal Aviation Administration (FAA) and the National Transportation Safety Board (NTSB) participated in a teleconference to discuss the FAA’s revised approach to address this recommendation, which is described below.

The FAA will first update Technical Standard Order (TSO) C90d, Cargo Pallets, Nets and Containers (Unit Load Devices - ULD), to include a scalable and tiered fire performance standard. TSO-C90e will improve flammability requirements for all new TSO ULD approvals by requiring these designs to meet the Class E cargo liner requirements of § 25.855, which requires materials to meet the 45 degree and vertical Bunsen burner test requirements. The new flammability requirements will effectively screen out highly flammable materials such as polypropylene.

TSO-C90e will also create a new Fire Resistant Container (FRC) classification tier, which will require a manufacturer to demonstrate containment of a Class A fire. All FRC flammability requirements will be based on SAE Aerospace Standard (AS) 8992, Fire Resistant Containers: Design, Performance, and Testing Requirements. We anticipate publishing TSO-C90e by December 31, 2020, pending SAE’s anticipated completion of AS8992.

Additionally, the FAA has issued new requirements for part 121 operators to meet part 5 Safety Management System (SMS) regulations since this recommendation was issued in 2012. These regulations can apply to part 135 operators under the voluntary SMS program. Pursuant to subpart C of part 5, these operators are required to apply safety risk management (SRM), which includes risk analysis and hazard identification for cargo operations. Leveraging SMS requirements allows for multiple methods to be utilized to achieve the intended safety outcome.

You previously told us that you intended to revise Technical Standards Order (TSO) C90, “Cargo Pallets, Nets and Containers (Unit Load Devices)” to incorporate new SAE aviation standards addressing the flammability of cargo container construction materials, and you planned to develop an advisory circular (AC) to address the use of fire-resistant containers based on the SAE aviation recommended practice. Because TSO C90 addresses two types of unit load devices (ULDs), you had planned to publish two separate revisions of the TSO; however, you now plan to publish a single revision that will address both types of ULDs (pallet and net and container).

We believe your updated plan is responsive to this recommendation. Pending the revisions to TSO C90 and the development and issuance of the new AC, Safety Recommendation A-12-69 remains classified OPEN--ACCEPTABLE RESPONSE.

-From Daniel K. Elwell, Acting Administrator: As previously reported, the Federal Aviation Administration (FAA) will incorporate new Society of Automotive Engineers (SAE) aerospace standards into a revision of Technical Standards Order (TSO) C90, Cargo Pallets, Nets and Containers (Unit Load Devices).

We will use the SAE documents to enhance unit load device (ULD) flammability requirements for new TSO authorizations. In our January 11 , 2018, letter to the Board, we mentioned publishing two revisions ofTSO-C90 in 2018. However. based on SAE standards publication dates, we plan to publish a s ingle TSO revision in 2019 that will incorporate new SAE standards for ULDs for both containers and pallets with nets.

For the container ULD, we will revise TSO-C90 to incorporate SAE AS8992, Fire Resistance Containers: Design, Performance, and Testing Requirements. SAE re-numbered this standard since our previous response, from AS6278 to AS8992. The AS8992 flammability requirements will be similar to the flammability requirements found in section 25.855 that are applicable to a container. AS8992 will require the oil burner test for panels detailed in section 25.855 and include a full-scale containment test. We believe these requirements will fulfill the intent of this recommendation by screening out use of polypropylene in the construction of ULD containers.

To address the ULD for pallets with nets, the TSO-C90 revision will include a Fire Containment Assembly, which includes improved flammability requirements. The revision will also add a Fire Containment Cover, which works as a system to contain a fire and meet the requirements of AS6453, Fire Containment Cover - Design, Performance, and Testing Requirements.

We anticipate SAE publishing AS8992 in mid-2019; we then expect to publish revised TSO-C90 in October 2019.

The FAA still plans to publish an Advisory Circular (AC) providing guidance on the operational use of FCCs. This AC will provide guidance to operators to use these enhanced ULDs to mitigate risk. The AC will be based on SAE Aerospace Recommended Practice (ARP) 6905, Fire Containment Cover Operation and Use, which is still under development. We anticipate publishing the AC in December 2019, following completion of the ARP.

In our May 23, 2017, letter about this recommendation, we said that it may be satisfied if an aviation standard (AS) being developed by SAE addresses the flammability of cargo container construction materials, and if the new AS is incorporated into a revision of Technical Standards Order (TSO) C90, “Cargo Pallets, Nets and Containers (Unit Load Devices).”

We note from your current letter that TSO-C90 addresses two types of unit load devices (ULDs). To address the first type of ULD, pallet and net, you plan to incorporate in TSO C90 new assembly testing requirements from SAE AS6453, “Fire Containment Cover (FCC)-Design, Performance, and Testing Requirements.” To address the second type of ULD, you plan a second revision of TSO-C90 that will incorporate new requirements from SAE AS6278, “Fire Resistant Container (FRC)-Design, Performance and Testing Requirements.” Finally, you plan to develop an advisory circular (AC) addressing operations with and use of FCCs that will be based on an SAE aviation recommended practice.

Pending the revisions to TSO-C90 and the development and issuance of the new AC, Safety Recommendation A-12-69 remains classified OPEN--ACCEPTABLE RESPONSE.

-From Daniel K. Elwell, Acting Administrator: In its May 23. 2017, letter, the Board stated that the Federal Aviation Administration (FAA) may satisfy this safety recommendation '"if the [aerospace standard (AS)] being developed by SAE addresses the flammability of cargo container construction materials and if the new AS is incorporated into a revision of Technical Standard Order (TSO) C90”.

The FAA is working on multiple fronts to address this safety recommendation. Within TSO-C90 there are two types of unit load devices (ULDs): 1. Pallet and Net; and 2. Container

For pallet and net ULDs, the FAA will revise TSO-C90 to incorporate the new assembly testing requirements of SAE AS6453, Fire Containment Cover (FCC) - Design, Performance, and Testing Requirements. We will relocate the requirements from TSO-C203, Fire Containment Covers, dated July I, 2014, to the revised TSO-C90. We anticipate publishing TSO-C90e in March 2018.

For container ULDs, the FAA will further revise TSO-C90 to incorporate the new requirements of SAE AS6278, Fire Resistant Container (FRC) - Design, Performance and Testing Requirements. We anticipate publishing TSO-C90f in December 2018.

In addition, the FAA will develop an Advisory Circular on the operation of FCC, based on an SAE Aerospace Recommended Practice.

I will keep the Board informed of the FAA 's progress on this safety recommendation and provide an update by November 30, 2018.

At a teleconference meeting on August 31, 2015, staff from the FAA and the NTSB discussed possible FAA actions that might satisfy this recommendation. The FAA agreed to consider three alternatives. On April 22, 2016, we indicated our belief that one of the alternatives would satisfy this safety recommendation: a new technical standards order (TSO) that included requirements for cargo container construction materials with low flammability (similar to that of other cargo compartment construction materials). In your current letter, you write that you have determined that none of the three alternatives discussed at the August 31, 2015, meeting would be beneficial.

You concluded a new TSO would not provide any additional safety benefit because of the existing flammability requirements in section 25.855 for materials used in cargo compartments, because fire containment covers (FCCs) are designed to deprive a fire of oxygen, and because fire-resistant containers (FRCs) may be used. Although FCCs and FRCs are allowed, they are not required. We note that, although requiring the use of FCCs and FRCs was among the alternatives discussed at the August 31, 2015, meeting, you have also decided not to require them. Ultimately, you have decided that you will not take any of the actions identified to satisfy this recommendation.

We note that you are currently working with SAE International to develop an aerospace standard (AS) for FRC flammability that will likely include requirements similar to section 25.855, and that this AS will be incorporated into a revision of TSO-C90, “Cargo Pallets, Nets, and Containers (Unit Load Devices).” We are concerned that you will not take any of the actions identified at our meeting, and that none of the alternatives that you discussed in your letter will satisfy the recommendation.

However, the recommendation may be satisfied if the AS being developed by SAE addresses the flammability of cargo container construction materials and if the new AS is incorporated into a revision of TSO-C90. Pending those stipulations, Safety Recommendation A 12 69 remains classified OPEN--ACCEPTABLE RESPONSE.

-From Michael P. Huerta, Administrator: At a meeting on August 31, 2015, staff from the Federal Aviation Administration (FAA) and the National Transportation Safety Board agreed the FAA would evaluate the following three options to reduce the flammability of cargo container construction materials: 1. Potentially issue a new Technical Standard Order (TSO) addressing flammability requirements for polypropylene containers; 2. Require the use of fire containment covers (FCCs) designed to deprive a fire of oxygen; and 3. Require the use of fire resistant containers (FRCs). The results of our review are provided below.

Option I: Upon further review, the FAA determined a new TSO with improved flammability requirements for non-TSO containers would not provide any additional safety benefits for the following reasons: • The flammability requirements of FCCs and FRCs are similar to the requirements in Title 14, Code of Federal Regulations (CFR) § 25.855, Cargo or baggage compartments; • FCCs and FRCs can be used where added protection against flres involving both cargo and shipping container materials is desirable; and

• FCCs and FRCs can be used in conjunction with, or in place of a TSO approved container, TSO approved pallet-net combination, or a non-TSO container, to contain or suppress a fire for a substantiated containment time. The current TSO used to approve containers, pallets, and nets is TSO-C90d, Cargo Pallets, Nets, and Containers (Unit Load Devices).

Options 2 and 3: There are no regulatory requirements to use an FCC or FRC. However, the FAA agrees with the Commercial Aviation Safety Team recommendation that FRCs and FCCs should be used to contain or suppress cargo fires. The FAA will evaluate the need for a safety alert for operators encouraging operators to use FCCs and FRCs.

A Society of Automotive Engineers International {SAE) aerospace recommended practice {ARP) will provide guidance for how FCCs should be used over flammable cargo and containers (such as polypropylene containers). The ARP will be referenced in an advisory circular due to be published in early 2018.

In addition, the FAA is currently working with SAE on the development of an aerospace standard (AS) for FRC flammability. The AS will include requirements similar to

At the August 31, 2015, meeting of NTSB and FAA staff, we were pleased to learn that the FAA is evaluating options to reduce the flammability of cargo container construction materials, including these:

1. Issuing a new TSO addressing flammability requirements for polypropylene containers 2. Requiring the use of fire containment covers designed to deprive a fire of oxygen 3. Requiring the use of fire resistant containers.

We recognize the FAA’s effort to reevaluate multiple TSOs that include flammability requirements for cargo container and accessory construction materials and encourage your support of industry efforts through the Commercial Aviation Safety Team (CAST), which may result in a separate TSO for fire-resistant cargo containers.

A new TSO that includes requirements for cargo container construction materials with low flammability similar to that of other cargo compartment construction materials would satisfy the intent of this safety recommendation. Accordingly, pending our review of a TSO that addresses the concerns specified in Safety Recommendation A-12-69, the recommendation is classified OPEN--ACCEPTABLE RESPONSE.

-From Michael P. Huerta, Administrator: In our previous letter dated April 9, 20 14, we stated that polypropylene containers are not governed by Federal Aviation Administration (FAA) regulations. On August 31, 2015, we met with the Board's staff and reported that polypropylene containers are not under the authority of any regulatory organization and therefore not required to meet any flammability criteria. The Board's staff expressed a strong desire for the FAA to provide the regulatory oversight of polypropylene containers not covered under an existing Technical Standard Order (TSO). We agreed to further evaluate other potential options to address the Board's request.

We are evaluating the following options: l) Potentially issue a new TSO addressing flammability requirements for polypropylene containers; 2) Require the use of fire containment covers designed to deprive a fire of oxygen; and 3) Require the use of fire resistant containers. In addition, we will reevaluate the flammability requirements for construction materials contained in the multiple TSOs for cargo containers and accessories and will provide the results of our findings in the next update.

Parallel to the review of the options identified above, the FAA supports the Commercial Aviation Safety Team and industry in the development of cargo area 'fire protection improvements that possibly could serve as an alternative to a material change. This joint effort is also promoting the development of a separate TSO for fire resistant containers, which is scheduled to be published by 2017.

I will keep the Board informed of the FAA's progress on this recomn1endation and provide an update by December 31, 2016.

Your letter stated that FAA regulations do not govern cargo containers other than unit load devices (ULD), and that the polypropylene containers tested in our study of the flammability of cargo containers are not ULDs because they are not used in an approved restraint system and are typically secured in pallet-net combination ULDs. Therefore, you regard such containers as either packaging or part of the cargo itself, rendering the flammability of the container the responsibility of the Pipeline and Hazardous Materials Safety Administration (PHMSA).

In investigating the flammability of common materials used to construct cargo containers, we found that many of these materials pose a serious risk to aviation safety. We continue to believe that the FAA has the responsibility for addressing the safety threat that the use of these materials poses. We are arranging a meeting with both FAA and PHMSA staff members to discuss and clarify the regulatory responsibilities. In the meantime, pending your taking the action specified in Safety Recommendation A-12-69, it is classified OPEN—UNACCEPTABLE RESPONSE.

-From Michael P. Huerta, Administrator: The Federal Aviation Administration (FAA) further reviewed the results of the Board's study on polypropylene containers and determined that polypropylene containers are not governed by FAA regulations. The FAA has responsibility for the standards associated with a Unit Load Device (ULD). A ULD is different from other containers on board the airplane in that it is designed for use in an approved aircraft restraint system. A ULD may consist of a pallet and net or it may be a container.

The polypropylene container is not a ULD. It is not used in the approved restraint system and typically is secured in a pallet-net combination ULD. It is considered by the FAA to be packaging or part of the cargo itself. The requirements associated with the polypropylene container are the responsibility of the Pipeline and Hazardous Materials Safety Administration. We are not aware of any service evidence that demonstrates cargo containers are inadequate for ordinary combustibles in relation to § 25.855.

The FAA is supporting the Commercial Aviation Safety Team in addressing safety standards for hazmat such as lithium batteries, in which improvements in fire related materials specifications are being addressed. SAE International has recently released a standard for fire containment covers that specifies improved fire resistance requirements for the pallet to be used with the cover. The FAA will incorporate these improved requirements into its technical standard order for the pallet.

I will keep the Board informed of the FAA's progress on this recommendation and provide an update by January 31, 2015.

We want to emphasize that regulation of the flammability of materials used to construct cargo containers is very limited, which reduces the effectiveness of the regulations at 14 CFR 25.855 for materials used in cargo compartments. Our study of cargo container fires identified collapsible containers, which are constructed out of corrugated polypropylene, as significant contributors to the intensity of a fire. We note that the FAA plans to review the results of this study to determine whether any action is needed. Pending our receipt and review of the FAA’s findings and completion of the recommended actions, Safety Recommendation A-12-69 is classified OPEN—ACCEPTABLE RESPONSE.

Notation 8477 (Dated 3/8/2013): The National Transportation Safety Board (NTSB) has reviewed the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) notice of proposed rulemaking (NPRM), “Hazardous Materials: Transportation of Lithium Batteries.” The notice requested additional comments about the impact of changes to the requirements for the air transport of lithium batteries that have been adopted into the 2013–2014 International Civil Aviation Organization Technical Instructions on the Transport of Dangerous Goods by Air (ICAO Technical Instructions) and subsequently incorporated by reference in the Hazardous Materials Regulations (HMR).

The NTSB notes that PHMSA is considering the long-term impacts of permitting shippers and carriers to choose between compliance with the existing HMR or compliance with the ICAO Technical Instructions, when transporting lithium batteries domestically by air. The NTSB further notes that PHMSA is seeking comment on whether to require mandatory compliance with the ICAO Technical Instructions for all shipments of lithium batteries by air, both foreign and domestic.

The NTSB believes that allowing domestic cargo shippers and carriers to choose between alternative standards for transporting lithium batteries would place carriers at greater risk when transporting such cargo in accordance with US regulations that currently provide less protection than the ICAO Technical Instructions. On April 14, 2010, the NTSB provided comments on the January 11, 2010, NPRM.

The 2010 NPRM proposed new requirements to address NTSB Safety Recommendations A-07-104, A-07-105, and A-07-107 through -109 that were issued as a result of the NTSB investigation of the February 7, 2006, in-flight cargo fire on a United Parcel Service Company (UPS) cargo airplane at Philadelphia International Airport in Philadelphia, Pennsylvania. The 2010 NPRM acknowledged that under the HMR, materials that pose a specific and serious air transportation risk are regulated more stringently than materials that pose less of a risk when transported by air, with lithium batteries being the current exception to this standard.

Included in the proposals at that time was the elimination of regulatory exemptions for packages of small lithium batteries. The NTSB stated that cargo shipments of small lithium batteries should be subject to the same packaging and identification requirements that apply to medium and large lithium batteries to increase the awareness of the risks associated with these batteries and to alert package handlers to exercise greater care when loading and unloading packages containing them.

-From Michael P. Huerta, Administrator: The Federal Aviation Administration (FAA) continues to support efforts to improve fire protection in transport airplane cargo compartments. Fire protection in aircraft cargo operations involves numerous considerations. We agree that improvements can be made in several elements of aircraft cargo fire protection systems, including improvements in installed aircraft systems and equipment and cargo containers. The FAA is working through the Commercial Aviation Safety Team (CAST) to address improvements for cargo fire protection, including the aircraft's capability to detect and control fires that could be exacerbated by the presence of hazardous cargo.

These CAST initiatives are expected to develop improved cargo fire containment systems to achieve safety improvements for air cargo operations.

To address Recommendations A-12-68 and -70, the FAA is working with industry and other Government agencies to evaluate the use of new fire extinguishing agents and delivery systems as well as advanced cargo containers that incorporate fire protection features that may detect and suppress a fire originating within the container. The FAA is evaluating whether a new higher-level standard would provide a safety benefit commensurate to the likely cost. Regarding Recommendation A-12-69, the FAA agrees that cargo container materials should not exacerbate a fire.

However, we are not aware of any service evidence that demonstrates FAA regulations for approved cargo containers are inadequate for ordinary combustibles. We will evaluate the results of the Board's cargo containment fire study to determine what, if any, further action may be needed to address this recommendation.

I will keep the Board informed of the FAA's progress on these safety recommendations and provide an update by December 2013.